Citrus tree named &#39;RBB7-34&#39;

ABSTRACT

The present invention relates to a new and distinct cultivar of citrus tree named ‘RBB7-34’. This triploid cultivar arose from a cross of the seed parent ‘LB8-9’ with pollen from a tetraploid selection of ‘Hamlin’ sweet orange that arose from colchicine treated embryogenic callus. ‘RBB7-34’ produces fruit that resemble Navel orange in size, shape and with the presence of a navel on the blossom end of the fruit, but with greatly enhanced internal and external pigmentation compared with ordinary Navel orange cultivars grown in the humid, sub-tropical Florida climate. Fruit of RBB7-34 are seedless even under intensive cross pollination pressure.

Latin name of the genus and species of the plant claimed: Citrusreticulata x Citrus sinensis.

Cultivar denomination: ‘RBB7-34’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of citrustree named ‘RBB7-34’. This triploid cultivar arose from a cross of theseed parent ‘LB8-9’ (U.S. Plant Pat. No. 21,356), which is a hybrid of‘Clementine’ x ‘Minneola’ tangelo) with pollen from a tetraploidselection of ‘Hamlin’ sweet orange that arose from colchicine treatedembryogenic callus. Embryo rescue and culture were performed to recovera seedling plant in vitro from the under-developed embryo that typicallyresults from interploid hybridization in citrus. A small shoot from theresulting in vitro seedling was then grafted to an etiolated Carrizocitrange rootstock seedling, acclimated, then grown out in thegreenhouse for a few years and finally planted in the field near LakeAlfred, Fla. The tree was first selected and propagated by top-workingto a few pre-existing rootstock seedling hybrids directly in the samefield; these top-worked trees fruited and produced true to type fruit.

SUMMARY OF THE INVENTION

The following are the most outstanding and distinguishingcharacteristics of ‘RBB7-34’. The cultivar is triploid, in contrast tothe diploid condition of ordinary Navel orange. It produces fruit thatresemble Navel orange in size, shape and with the presence of a navel onthe blossom end of the fruit (−70% of the fruit), but with greatlyenhanced internal and external pigmentation, compared with ordinaryNavel orange cultivars grown in the humid, sub-tropical Florida climate(see FIGS. 4-7). RBB7-34 fruit more closely resemble fruit of Navelorange grown in a Mediterranean climate. In addition to improved color,RBB7-34 fruit also have substantially higher ° Brix and titratableacidity, compared to ordinary Navel orange cultivars grown in the sameblock and harvested at the same time (° Brix/acid=15.2-16.6/1.0 vs.10.2/0.6, in December 2013). Though not quantified, RBB7-34 fruit havemore obvious and pleasant flavor and aroma than ordinary Navel fruit, aswell. They mature in the same season as the ‘Glen’ Navel orange,probably the most widely planted Navel cultivar in Florida, usually inDecember through January. Though Navels are usually seedless, they canpossess some seeds under high mixed cross pollination conditions. Thefruit of RBB7-34 are seedless even under intensive cross pollinationpressure.

BRIEF DESCRIPTION OF THE DRAWINGS

‘RBB7-34’ is illustrated by the accompanying photographs which show someaspects of the tree's form, foliage, and fruit. The colors shown are astrue as can be reasonably obtained by conventional photographicprocedures.

FIG. 1—Shows the overall mature plant growth and fruiting habit inDecember 2013. The tree was beginning to show the effects of citrusgreening disease, or HLB, which was spreading rapidly through theorchard at this time.

FIG. 2—Shows a young tree (˜2 years) grown in a pot under openhydroponics management and in an enclosed structure. The photo was takenJanuary 2017. The budwood source was very juvenile, as can be seen bythe presence of conspicuous thorns. More mature budlines that have beendeveloped are less thorny. The foliar characteristics are typical ofthose observed in triploid citrus, with thicker leaves and roughertexture resulting from larger oil glands, as opposed to the thosecommonly found on typical diploid navel orange trees.

FIG. 3—Shows a cluster of mature fruit and leaves on another young tree(˜2 years) tree grown in a pot under open hydroponics management and inan enclosed structure. The photo was taken January 2017. The budwoodsource was very juvenile, as can be seen by the presence of conspicuousthorns, as well as the more coarse texture of the fruit rind, typicalcharacteristics of vigorous juvenile orange trees. The foliarcharacteristics are typical of those observed in triploid citrus, withthicker leaves and rougher texture resulting from larger oil glands, asopposed to the those commonly found on typical diploid navel orangetrees.

FIG. 4—Shows a close-up of the mature fruit, ‘Glen’ Navel left,characterized by pale green-yellow-orange color, and RBB7-34 right,characterized by deeper orange color. Photo taken December 2013.

FIG. 5—Shows a close-up of the blossom, or navel, end of the maturefruit, ‘Glen’ Navel left, characterized by pale green-yellow-orangecolor, and RBB7-34 right, characterized by deeper orange color. Note theconspicuous navel structure of each. Photo taken December 2013.

FIG. 6—Shows a close-up of the mature fruit cut equatorially, ‘Glen’Navel left, characterized by pale yellow-orange flesh color and a fewseeds, and RBB7-34 right, characterized by deeper orange color and theabsence of seeds. Photo taken December 2013.

FIG. 7—Shows an additional close up of the mature fruit cut equatoriallyupfront, and 3 other fruit showing external color and appearance. Phototaken January 2014.

DETAILED BOTANICAL DESCRIPTION

The following detailed description sets forth the distinctivecharacteristics of ‘RBB7-34’. The present botanical description is thatof the cultivar grown as a 7 year-old tree growing on ‘Carrizo’rootstock in Lake Alfred, Fla. The colors (except those in common terms)are described from RHS Colour Chart published by The Royal HorticulturalSociety in London (second edition), in association with the FlowerCouncil of Holland.

-   Phenotypic description of ‘RBB7-34’-   Classification:    -   -   Botanical.—Citrus reticulutu x Citrus sinensis.        -   Common name.—Mandarange.-   Parentage:    -   -   Female parent.—‘LB8-9’ (U.S. Plant Pat. No. 21,356) mandarin            hybrid.        -   Male parent.—‘Hamlin’ sweet orange 4x, unreleased,            unpatented breeding parent from the UF-CREC citrus breeding            program.-   Tree:    -   -   Ploidy.—Triploid.        -   Size.—Medium.        -   Height.—3.1 m.        -   Tree spread.—3.2 to 3.8 m.        -   Vigor.—Moderate vigorous.        -   Density.—Canopies are moderately dense.        -   Form.—Round-shaped with mostly lateral branches growing at            low to medium angles. Branches with fruit exhibited            drooping.        -   Growth habit.—Upright and lateral growth with low-medium            angle.-   Trunk:    -   -   Trunk diameter.—15 cm in diameter at 30 cm above from            ground.        -   Trunk texture.—Rough with thorns.        -   Trunk bark color.—RHS N199A (greyed-brown); irregularly            striated with RHS N189A (greyed-green).-   Branches:    -   -   Crotch angle.—First crotch from 35- to 40-degree angle,            middle crotch formed 120-degree angle.        -   Branch length.—3 m from the first crotch to the tip of the            branch.        -   Branch texture.—Relatively rough with small thorns or            spines.        -   Branch color (shoots from previous flush, hardened, and 4 to            5 mm in diameter.—): RHS 138A (green).-   Leaves:    -   -   Size (lamina average).—Length: 88.8 mm Width: 53.2 mm L/W            ratio: 1.67.        -   Thickness.—Slightly thicker than regular and average            mandarin leaves when compared to commercial mandarin            hybrids, typical of triploid citrus hybrid plants.        -   Type.—Simple.        -   Shape.—Elliptical.        -   Apex.—Retuse.        -   Base.—Acute to sub-obtuse.        -   Margin.—Entire and slightly undulate.        -   Surface.—Upper surface: Glabrous Lower surface: Medium veins            that are pinnately netted.        -   Color.—Upper surface (adaxial): RHS 137A (green) Lower            surface (abaxial): RHS 146B (yellow-green).        -   Petiole.—Shape: Brevipetiolate (shorter than leaf lamina);            junction between petiole and lamina is articulate. Width            (petiole wing): Very narrow Shape (petiole wing): Obovate            Length: 15 to 17 mm Width: 3.6 to 3.9 mm Color: RHS 137A            (green).-   Flowers and flower buds:    -   -   Type.—Hermaphrodite.        -   Bearing.—Flowers grown from leaf axillaries and leaf            terminals in single flower and in small clusters of 1-3            flowers; most single flowers grown from leaf axillaries;            each flower branch consists of 6 to 14 flowers.        -   Flower diameter.—Fully open flower with average diameter of            38.2 to 38.6 mm.        -   Flower depth.—Typical flower with average depth of 16.2 mm.        -   Flower blooming period.—First bloom observed: Feb. 20, 2012            Full bloom observed: Feb. 25, 2012.        -   Flower bud size.—Length: Initial visible flower bud with 2.8            mm in length; mature flower bud with 20 mm in length.            Diameter: Initial visible flower bud with 3.0 mm in            diameter; mature flower bud with 20 mm in diameter.        -   Flower bud shape.—Initial visible flower bud: Round ball            shape Mature flower bud: Elongated olive shape.        -   Flower bud color.—Initial visible flower bud: RHS 138B            (green) Mature flower bud: RHS NN155C (white) with RHS 151C            (yellow-green) spots distributed at tip of the flower bud.        -   Flower petals.—Shape: Flat spatula shaped Apex shape: Smooth            acute shaped Base shape: Even obtuse Color: Upper surface            with RHS NN155C (white); lower surface with RHS NN155B            (white) with RHS 151C yellow-green) spots distributed toward            to the petal apex. Margin: Smooth.        -   Flower sepal.—Number: 5 per flower Shape: Delta shaped with            acute angle at apex. Length: 3.8 mm Width: 3.6 mm Apex            shape: Triangle-shaped Margin: Smooth Color: Upper surface            with RHS 145D (yellow-green); lower surface with RHS 145C            (yellow-green).        -   Fragrance.—Moderately fragrant.        -   Flower pedicel.—Length: 7.2 to 7.8 mm Diameter: 1.5 to 1.7            mm Color: RHS 145B (yellow-green).        -   Reproductive organs.—Fertility: Appears self-fertile. Stamen            length: 13.6 to 13.8 mm Anther length: 3.6 mm Anther Width:            1.2 to 1.4 mm Anther color: RHS 22D (yellow-orange) Anther            filament length: 10 to 11.2 mm Pollen amount: Low Pollen            color (general): RHS 16A (yellow-orange) Pistil number: 1            Pistil length: 13.2 to 13.5 mm Pistil color: RHS 145D            (yellow-green) Style length: 9 mm Style diameter: 1.8 to 1.9            mm Style color: RHS 145D (yellow-green) Ovary shape:            Oval-shaped Ovary diameter: 3.9 mm Ovary color: RHS 143C            (green).-   Fruit:    -   -   Size.—Uniform.        -   Average height.—73.1 to 75 mm.        -   Average width.—79.1 to 81.5 mm.        -   Average weight (per individual fruit).—238.5 g.        -   Shape.—Round.        -   Shape (cross-section): Round.        -   Apex.—Truncated, 70% of the fruit appear to have navel.        -   Base cavity diameter.—6.8 to 7.0 mm.        -   Base.—No neck.        -   Harvesting.—First pick around December 20th based on season            and rootstock; last pick around late January though fruit            continue to hold on the tree for a longer time (based on            season and rootstock).        -   Fruit stem (short stem connecting the fruit).—Length: 7.9 to            9.9 mm Diameter: 4.0 to 5.0 mm Color: RHS 195A            (greyed-green) with RHS 197A (greyed-green) strip.-   Rind:    -   -   Adherence.—Albedo (mesocarp) to flesh (endocarp) is            medium-strong, similar to regular navel sweet orange, and is            evenly distributed from base to apex.        -   Thickness.—2.7 to 3.4 mm.        -   Texture.—Smooth.        -   Color.—Flavedo (epicarp): Ranges from RHS 23A            (yellow-orange) to RHS 24B (orange) Albedo (mesocarp): RHS            18C (yellow-orange).        -   Stylar end.—Slightly open and 70% of the fruit have navel.        -   Rind oil cell density.—206 oil cells/square cm.-   Flesh:    -   -   Number of segments.—Average between 11 to 12 segments per            fruit.        -   Segment walls.—Medium-soft with sufficient strength to            maintain integrity as separated.        -   Juice.—Abundant.        -   Color.—Uniformly RHS 23A (yellow-orange).        -   Texture.—Medium-soft.        -   Vesicles.—Length: 12.2 to 13.3 mm Diameter (thickness): 3.5            to 4 mm.        -   Eating quality (tested at Mid-December).—Soluble solids            (average): 15.2 to 15.4 Brix Acidity (average): 1.0 to 1.2            Ratio: 12.7.-   Seeds:    -   -   Type.—Seedless.

What is claimed is:
 1. A new and distinct citrus tree called ‘RBB7-34’as illustrated and described herein.